This patent document relates to magnetic resonance image (MRI) technologies.
The lungs are primarily responsible for gas exchange, as well as a number of other functions. Ventilation of the lungs refers to the intake and removal of air in/out of the lungs, which involves the mixing of inspired gas (inhaled gas that is humidified and at body temperature) with alveolar gas for gas exchange of oxygen (O2) and carbon dioxide (CO2) in the alveoli of the lungs. Perfusion refers to the delivery of blood to capillary beds of a biological structure, e.g., alveoli in the lungs.
MRI is a medical imaging technique that applies a magnetic field and a pulse of radio frequency (RF) energy to produce an image used for imaging internal biological structures, e.g., the lungs. MRI is based on the property of nuclear magnetic resonance (NMR). NMR is a physical property in which the nuclei of atoms absorb and re-emit electromagnetic energy at a specific resonance frequency in the presence of a magnetic field. The absorption and reemission of energy can be dependent on the strength of the magnetic field and the magnetic property of the atoms (e.g., atoms whose nuclei possesses magnetic spin).